V2O5-Doped M2+Cu2Nb2O8 Compounds (M2+= Zn, Co, Ni, Mg & Ca) for Microwave Dielectric LTCCs
The copper-niobates, M2+Cu¬2Nb2O8 (M2+ = Zn, Co, Ni, Mg or Ca) have good microwave dielectric properties when sintered between 985 – 1010oC, and 1110oC for CaCu¬2Nb2O8. Therefore they would be potential dielectric Low Temperature Co-fired Ceramic (LTCC) materials if they could be made to sinter below 960oC (melting point of silver). To this end, additions of 3wt% V2O5 were made to ZnCu2Nb2O8, CoCu2Nb2O8, NiCu2Nb2O8, MgCu2Nb2O8 and CaCu2Nb2O8, and their sintering and dielectric behaviour was investigated for samples fired between 800 and 950oC. Doping lowered sintering temperatures to below the 960oC limit in all cases. Doping had the general effect of reducing r, density, Qf and f, although doped CaCu2Nb2O8 had a Qf value of 9300 GHz, nearly four times that of the best undoped sample. When doped and undoped samples all fired to 935oC were compared, all doped samples had greater r and density, and all except ZnCu2Nb2O8 had a smaller f.
Paula Maria Vilarinho
R. C. Pullar et al., "V2O5-Doped M2+Cu2Nb2O8 Compounds (M2+= Zn, Co, Ni, Mg & Ca) for Microwave Dielectric LTCCs", Materials Science Forum, Vols. 514-516, pp. 264-268, 2006